GHSA-2jhm-w3mp-jcwr

Suggest an improvement
Source
https://github.com/advisories/GHSA-2jhm-w3mp-jcwr
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-2jhm-w3mp-jcwr/GHSA-2jhm-w3mp-jcwr.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-2jhm-w3mp-jcwr
Aliases
Downstream
Published
2026-08-10T00:31:42Z
Modified
2026-10-02T23:40:41Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
Summary
NLTK network URL validation permits SSRF to RFC 6598 shared-address-space hosts
Details

A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch. The nltk.pathsec.validate_network_url() function, intended to prevent SSRF by rejecting internal network addresses, fails to reject IPs in the RFC 6598 shared address space (100.64.0.0/10). This occurs because Python's ipaddress module does not classify such addresses as is_private or is_global, and the current guard only checks is_private and a few explicit categories. An attacker who can influence a URL passed to NLTK's network-loading helpers can exploit this vulnerability to make a strict-mode application send requests to shared-address-space hosts, potentially exposing non-public infrastructure reachable from the application host. The impact is limited to SSRF-style confidentiality exposure, with no code execution claimed.

Database specific 
{
    "cwe_ids":  [
        "CWE-918"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-10-02T23:11:23Z",
    "nvd_published_at":  "2026-08-09T23:16:35Z",
    "severity":  "LOW"
}
References

Affected packages

PyPI / nltk

Package

Name
nltk
View open source insights on deps.dev
Purl
pkg:pypi/nltk

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.10.0

Affected versions

2.*
2.0.1rc2-git
2.0b4
2.0b5
2.0b6
2.0b7
2.0b8
2.0b9
2.0.1rc1
2.0.1rc3
2.0.1rc4
2.0.1
2.0.2
2.0.3
2.0.4
2.0.5
0.*
0.8
0.9
0.9.3
0.9.4
0.9.5
0.9.6
0.9.7
0.9.8
0.9.9
3.*
3.0.0b1
3.0.0b2
3.0.0
3.0.1
3.0.2
3.0.3
3.0.4
3.0.5
3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.3
3.4
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
3.5b1
3.5
3.6
3.6.1
3.6.2
3.6.3
3.6.4
3.6.5
3.6.6
3.6.7
3.7
3.8
3.8.1
3.9b1
3.9
3.9.1
3.9.2
3.9.3
3.9.4

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-2jhm-w3mp-jcwr/GHSA-2jhm-w3mp-jcwr.json"